Bubble foam water is required in many water taps including ordinary homes and in commercial facilities. The impression from use of the bubble foam water in washing is quite gentle. Therefore the bubble foam water is preferably used in washing glasses and the dishes because cracking or damage to the surface of the glasses and the dishes can be avoided. The bubble foam water hardly rebounds even if it hits the surface of the glasses and the dishes in washing, so there is no fear of splashing water around the sink and deteriorating the environment. Therefore, the bubble foam water preferably is used in many water taps not only in ordinary homes but also in the railway station, in the public facilities, in the laboratory in the research institute, and so on.
In the prior art, one of the methods for making the bubble foam water is attaching a water saving aerator to the water delivery devices such as a water tap. The water saving aerator in the prior art comprises air ventilation holes for in taking outer air to the water flow as a basic structure. The outer air is mixed with the water flow via the air ventilation holes. In addition, the opening of the water delivery devices is covered by the net for cutting the water flow into small pieces. The bubble foam water is generated by mixing the outer air via air ventilation hole and cutting the water flow by installing several nets to the opening of the water delivery devices for cutting the water flow into small pieces.    Patent prior art 1: JP H09-095985    Patent prior art 2: JP 2000-104300